<html xmlns="http://www.w3.org/1999/xhtml">

<head>
<script>
function foo()
{
  var mo = document.getElementById("mo");
  mo.removeChild(mo.firstChild);
}
</script>
</head>

<body onload="foo();">

<div><math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
<mrow>
  <mi>x</mi>
  <mo id="mo">=</mo>
  <mi>y</mi>
  </mrow>       
</math></div>

</body>
</html>
